Comments for What about ethical shopping for coffee?

I wanted to suggest Green Tree Coffee and Tea as a socially responsible vendor. I buy from them directly. Their whole bean coffees are Rain Forest Alliance Certified.
This is some info I gleaned from one of their Newsletters: "Green Tree is committed to procuring the finest tasting, finest quality coffee from farmers who are dedicated to sustainable growing practices.

Rainforest Alliance growers adhere to farm management guidelines developed by the Sustainable Agriculture Network and earn the Rainforest Alliance Certified seal of approval. The certification guarantees that the farm is managed according to the highest social and environmental standards.

-excerpted and adapted from The Rainforest Alliance, www.rainforest-alliance.org"

I like to buy fair trade items, but I find that the fair trade coffe seems acidic. Is it roasted differently than other brands, or use different beans? Is there a good coffe that is low acid for people with sensitive stomachs. I love the flavor but don't want the heartburn!
Thanks